what camp are you in?

[mtrycrafts]

Make that Mtry and myself. Gotta luv the boombox!

Great company but yours is much bigger than mine. LOL

 

[mtrycrafts]

When i started this thread i was trying to get a feel as to who basically listens to equipment or adheres to charts, graphs and measurements when making a buying decision. Hence the "what camp are you in?" headline. Now i'm really confused 54 posts later! Mtry and wmax appear to think properly designed and well-functioning units that measure alike will sound alike, yet adhere strongly to double blind testing which involves critically LISTENING. Dan on the other hand, seems to be a charts kinda guy, wants nothing to do with dbt, yet appears to agree with me that audible diffs can exist between said gear. NOW WHAT?

Why do folks in science continue to retest their previous findings? Perhaps to be sure, perhaps to see if something was missed on previous testing, etc.

Just a couple of things though. Components don't really have to measure alike just below threshold of detection. A .01 thd and a .0001 thd are not even close but well below detection, certainly with music.

I would only recommend DBT when one is hesitant about their perception or ideas about modern components. I would not do one if they meet the well designed category. What for?
Now what? The information is out there if one wants to expand their horizon. As the saying goes, you can lead a horse to water...

 

[mtrycrafts]

.....guys, it's folly to say different equipment sounds the same concerning receivers and slave power....every manufacturer assigns a sonic signature they hope will bring home the bacon......

Can you support your assertions about these different makers assigning a sonic signature? I'd be interested in a few example while these components are considered well designed. And yes, rest assured, these sonic signature differences can be measured.
It is time that supporting evidence is provided by somebody. Maybe I have to change my tune so I could be part of that special group

 

[Dan Banquer]

What camp are you in

.....guys, it's folly to say different equipment sounds the same concerning receivers and slave power....every manufacturer assigns a sonic signature they hope will bring home the bacon......

Not only do we do that but we install video cameras to spy on you. Care to fess up about all those kinky things you do while the music is playing? or do we have to release the video?
d.b.

 

[Dan Banquer]

What camp are you in

From our Resident Audio Expert Mr. Mytrcrafts:
"Just a couple of things though. Components don't really have to measure alike just below threshold of detection. A .01 thd and a .0001 thd are not even close but well below detection, certainly with music."

A 0.01% THD if predominantly made up of higher order distortion, I suspect will be readily audible. If the 0.01% THD is second order distortion with a small amount of third it will be virtually inaudible. The study by Jamie Moir done years ago really does not approach the characterization of harmonic distortion at all. The studies done on human ear masking were done many years ago, you may wish to hit the library for that one, or a recent article in Multi Media Manufacturer by Keith Howard. I love the first paragraph of that article.
d.b.

 

[mtrycrafts]

But there is one major problem with DBT's and audio; it is not accepted by the majority of consumers, who could really care less, nor is it fully accepted by the many recording engineers, and designers. Do you think there might be a reason for that?
I suppose you could just chalk it all up to ignorance, but that still wouldn't be convincing for many folks now would it? And why after all these years are so many people not impressed with audio DBT testing?
d.b.

I could say the same thing about many consumer marketplace. Homeopathic medicines are not accepted by science, yet the fortunes made in that marketplace. Staggering.
How about psychics? Why are so many are enamored by them? Talking to the dead with luminaries in that snake oil field such as Sylvia Brow, or John Edwards. Why do so many claim to be abducted by aliens????

How about Intelligent design? From the President on down to school boards???

No one is immune from bs, hype, mythology, voodoo, no one.

You may want to ask yourself if you are willing to use those homeopathic medicines. Certainly no DBT was involved there.

You would be well advised to read this link and the link within it. Your complete trust in perception is not sitting on such a great foundation:

Now you hear it, now you don't
http://groups.google.com/group/rec.audio.high-end/browse_thread/thread/2d3d415422f4b660/67f6ac891b8f37f9#67f6ac891b8f37f9

But, who am I to argue with science??? I will follow greats like Dr Toole and many others such as he. You will follow you convictions as it should be.

 

[WmAx]

A 0.01% THD if predominantly made up higher order distortion I suspect will be readily audible. If the 0.01% THD is second order distortion with a small amount of third it will be virtually inaudible. The study by Jamie Moir done years ago really does not approach this at all.

The James Moir study specifically investigated a typical spectrum of THD as found in typical solid state amplification. It is true that the study he conducted, or the ones that he referenced, did not specifically investigate predominantly high order harmonics. But it is not typical for properly operating equipment to produce predominantly high order harmonics. Moir is well aware of the relevance of high order harmonics(or more accurately, the specific frequency bands and the combination of harmonics), so I hardly think that he overlooked this issue. In fact, Moir was responsible for alot of the early work (beginning in the 1950's) on high order harmonics prior to his 1981 Wireless World article/study.

-Chris

 

[mtrycrafts]

A 0.01% THD if predominantly made up of higher order distortion, I suspect will be readily audible. d.b.

You suspect??? No data but you suspect??? Please, get better credible data, not suspicions.
And, get some DBT data on audible differences of components. No data, you have nothing.

 

[PENG]

Obviously, if someone is doing *both*, then they qualify, and could be classified as *both*.

-Chris

Well Chris, that's a smart answer. You know full well what I meant and I am sure you also know what engineers and scientists do.

 

[genesound]

As a 30 year vet in pro audio I always look at the specs. But I generally just consider it a look, not a listen. I hear things in my van that I wish my home system would reproduce. It's just not gonna happen. The best situation would be to hookup the mixdown engineer (or maybe the mastering engineer if it's been way smashed) to the DBT. ONLY THAT PERSON is actually qualified to relate the accuracy of the reproduction. Got it?

 

[Dan Banquer]

What camp are you in

The James Moir study specifically investigated a typical spectrum of THD as found in typical solid state amplification. It is true that the study he conducted, or the ones that he referenced, did not specifically investigate predominantly high order harmonics. But it is not typical for properly operating equipment to produce predominantly high order harmonics. Moir is well aware of the relevance of high order harmonics(or more accurately, the specific frequency bands and the combination of harmonics), so I hardly think that he overlooked this issue. In fact, Moir was responsible for alot of the early work (beginning in the 1950's) on high order harmonics prior to his 1981 Wireless World article/study.

-Chris

Yes, but it's not in that article.
d.b.

 

[Dan Banquer]

What camp are you in

I could say the same thing about many consumer marketplace. Homeopathic medicines are not accepted by science, yet the fortunes made in that marketplace. Staggering.
How about psychics? Why are so many are enamored by them? Talking to the dead with luminaries in that snake oil field such as Sylvia Brow, or John Edwards. Why do so many claim to be abducted by aliens????

How about Intelligent design? From the President on down to school boards???

No one is immune from bs, hype, mythology, voodoo, no one.

You may want to ask yourself if you are willing to use those homeopathic medicines. Certainly no DBT was involved there.

You would be well advised to read this link and the link within it. Your complete trust in perception is not sitting on such a great foundation:

Now you hear it, now you don't
http://groups.google.com/group/rec.audio.high-end/browse_thread/thread/2d3d415422f4b660/67f6ac891b8f37f9#67f6ac891b8f37f9

But, who am I to argue with science??? I will follow greats like Dr Toole and many others such as he. You will follow you convictions as it should be.

You really should get out and hit the library, there is a world of relevant information that is available to you. Yes Dr. Toole has made some contributions, but your close mindedness to the so many relelvant studies and your lack of knowledge about the basics of electroincs show me you have limited your scope down to few papers. It's big world out there, but hey, maybe you need those kind of limitations to make you feel more comfortable and secure.
BTW: There is still a pretty hefty debate on harmonic distortion and audibility, and what I have learned through design over the years is "kill the upper harmonic distortion".
Audio is an ongoing process.

d.b.

 

[Dan Banquer]

What camp are you in

As a 30 year vet in pro audio I always look at the specs. But I generally just consider it a look, not a listen. I hear things in my van that I wish my home system would reproduce. It's just not gonna happen. The best situation would be to hookup the mixdown engineer (or maybe the mastering engineer if it's been way smashed) to the DBT. ONLY THAT PERSON is actually qualified to relate the accuracy of the reproduction. Got it?

There is much merit in what you say.
d.b.

 

[Dan Banquer]

What camp are you in

I have some further thoughts on DBT testing.
Suppose you have amplifier X and Y, and you are doing a DBT test into Speaker A. Speaker A has resistive load. You determine through the DBT that there is no difference between amplifier X and Y. The same test is done with Speaker B. Speaker B has a much more reactive load that has a phase angle of +/- 45 degrees at certain points in the crossover. In a DBT test of the amplifier X and Y you could have two possible outcomes. One outcome could be that amplifier X shows differences between amplifier Y due to more or less distortion due to the reactive load. You could also find no difference because the program material did not "hit" that +/- 45 degree phase angle at all and you get a null result.

Still think DBT testing is the ultimate answer?
d.b.
P.S. Neither amp is clipping during any part of the test.

 

[MacManNM]

Excellent point Dan. This is a situation that is very common. As Roger Russell says "good amplifiers CAN sound the same".

 

[WmAx]

Still think DBT testing is the ultimate answer?
d.b.
P.S. Neither amp is clipping during any part of the test.

But the issue with power factor(which you indirectly refer to when talking about phase angle vs. frequency into a reactive load) does have to do with clipping. If a load requires more power than the amplifier can cleanly produce in specific instances where the amplifier has to produce more power to drive the load to a certain amplitude due to a high degree phase angle than was initially accounted for(typically power factor is not considered, but instead a resistive load), then it may clip. That is the only substantial concern for phase angle of which I am aware; how it relates to power factor. I.E.; An amplifier would be working twice as hard as one thought at a 45 degree angle of phase as compared to the resistive load estimate.

As far as blind protocols being an ultimate answer, it is the only answer that so far exists for reasonably accurate listening tests are concerned. It should be noted that the issues you bring up while attempting to criticise DBT are not caused by DBT, they are caused by not testing for them with specific test(s). Every variable you brought up so far can be implimented into a test using a blind testing protocol. In fact, the points you bring up are applicable to a non-blinded testing protocol. Of course, the non-blinded test will have many more potential flaws.

-Chris

 

[Dan Banquer]

What camp are you in

"But the issue with power factor(which you indirectly refer to when talking about phase angle vs. frequency into a reactive load) does have to do with clipping. If a load requires more power than the amplifier can cleanly produce in specific instances where the amplifier has to produce much more power to drive the load to a certain amplitude due to a high degree of phase angle than was initially accounted for, then it may clip."

WRONG! This is about distortion into a reactive load. Not Clipping. And BTW: DBX in the 80's found out more about this so it's nothing new either.
d.b.

 

[WmAx]

A The best situation would be to hookup the mixdown engineer (or maybe the mastering engineer if it's been way smashed) to the DBT. ONLY THAT PERSON is actually qualified to relate the accuracy of the reproduction. Got it?

The DBT as discussed here is not attempting to show accuracy. It is attempting to show difference. If no difference is detected, thus one can not identify one from the other, then one can not then judge one as more accurate.

-Chris

 

[WmAx]

WRONG! This is about distortion into a reactive load. Not Clipping. And BTW: DBX in the 80's found out more about this so it's nothing new either.
d.b.

Wrong? So if an amplifer that can produce 50 watts before clipping into a resistive load has to deliver 100 watts into reactive load at a specific frequency band where a 45 degree angle phase in impedance occurs, then this 50 watt-limit amp will not clip when it is attempting to produce 100 watts?

So far as distortion when an amplifier is not clipping: it remains well below known human thresholds in properly designed amplifiers with normal reactive loads. If one want to bring up obviously incompatible loads or a poorly designed amplifiers, then these are special/unique situations that must be addressed specifically, in that they are not typical audio equipment behaviour(s).

-Chris

 

[Dan Banquer]

What camp are you in

Your mistake here is that you still think this is all about power. It isn't. This is the typical mistake of novices who don't understand the technology, it's limits, and read only some of the papers that deal only with a part of the problem. I suspect this is one of the reasons that the DBT for audio power amps is not generally accepted as the absolute definitive test. To many of us it's just another tool in the box so to speak. It's a big world out there, and you can spend a lifetime investigating it.
Audio is an on going process.
d.b.